Many different types of portable electronic devices are currently available which use a small display screen, e.g. a liquid crystal display, and a keyboard for entering data into the device. Examples of such devices include pocket calculators, personal digital assistants (PDA), and cellular telephones. More recently, a new type of device has become available which combines the functions of a cellular telephone and a personal digital assistant. Particularly in the case of the latter type of device, there is a strong desire to reduce the overall size of the device in order to allow it to be more easily carried by a user.
EP 0534478 describes a portable telephone set including an electronic notebook function, i.e. of the combined cellular telephone/PDA type. The device has a body portion on which a number of electronic notebook keys are provided. A lid is hingeably connected to the body portion, the lid having telephone keys provided on both its inner and outer surfaces. When the lid is closed over the body portion, the notebook keys are covered by the lid and only the telephone keys provided on the outer surface of the lid are accessible. When the lid is open, both the telephone keys on the lid's inner surface and the notebook keys are accessible. The body portion is provided with an elongate display which is visible both when the lid is closed and when it is open.
EP 0472361 describes a similar type of portable device having a body portion on which are provided a number of notebook keys and a display screen. A lid portion is hingeably connected to the body portion and when the lid is in the closed position the lid partially covers the display. On the outer surface of the lid there are provided a number of telephone keys which allow a user to make a telephone call when the lid is closed. A number of additional notebook keys are provided on the inner surface of the lid.